Ingredient
Tillage radish
Raphanus sativus
Also known as: daikon radish, Raphanus sativus var. longipinnatus, forage radish
Brassica cover crop with a 12–24-inch taproot that biologically breaks compaction in the upper soil profile — the right ingredient when a field has plow-pan or hardpan that's limiting root depth in the cash crop. The radish punches deep, scavenges N from sub-soil layers (capturing 50–150 lb N from depths beyond what most crops reach), and winter-kills cleanly in Zone 6 and colder, leaving the holes as drainage-and-aeration channels through the spring. Seeded August through early September; absolutely must be planted on time — late seeding gives small radishes that don't deliver the compaction benefit.
Inputs / outputs
- Seeding: 8–10 lb/acre solo, 4–6 lb/acre in mixes; August 1 through September 5 (timing critical)
- Cold tolerance: winter-kills at ~25°F sustained; reliable kill in Zone 6 and colder
- Termination: winter-kill is the standard; otherwise mow + tillage before bolting in spring
- Root depth: 12–24 inches in well-drained soil; less in compacted clay (which is where it’s most useful — the radish punches through)
- N scavenged: 50–150 lb N/acre from sub-soil layers other crops can’t reach
- Decomposition odor: the spring melt of frost-killed radish produces a notable [[cabbage|cabbage]] / sulfur smell — neighbors notice
Solves / unlocks
- Biological subsoiling (replaces or supplements mechanical compaction-breaking)
- Sub-soil N scavenging (depth most cover crops can’t reach)
- Improved spring infiltration through the radish channels
- Weed suppression via dense fall canopy
- Wireworm and root-knot nematode suppression (brassica glucosinolate biofumigation, weak)
Constraints
- Late seeding fails — by mid-September the radish doesn’t size up enough to break compaction; this is the most common failure mode.
- Doesn’t survive winter in warm zones — Zone 7+ may need mowing or tillage termination; gets weedy.
- Brassica rotation conflict — don’t plant radish before [[cabbage|cabbage]], [[broccoli|broccoli]], kale, or other brassicas (shared diseases, especially clubroot).
- Smell — spring melt of frozen radishes produces a sulfurous odor; not a neighborhood-friendly choice in residential agriculture.
Source
- USDA Plant Guide
- Penn State Extension Tillage Radish trials: https://extension.psu.edu/
See also
Auto-generated from this entry’s typed relations: frontmatter, grouped by relation type so the editorial signal isn’t flattened.
- Member of: [[ingredient]]
- Combines with: [[cereal-rye]] · [[crimson-clover]]
What links here, and how
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Scientific
combines with
- Cereal rye fall biculture: radish breaks compaction and scavenges N to depth, rye holds the field through winter once the radish winter-kills
contains
- Ecosystem toolkit cover crop / brassica compaction-breaker + N-scavenger
combines
- Recipe: vegetable-rotation cover-crop cocktail the brassica component — compaction-breaking, sub-soil N scavenging
3 inbound links · 3 outbound